Stephen K. Western, C. L. V. Aiken
A residual Bouguer gravity anomaly map of southern New Mexico, West Texas, and northeast Mexico has been constructed and analyzed. Residual anomalies have been computed by using a Bouguer reduction datum defined by the regional elevation of topography. This same approach when applied to Arizona and northern New Mexico brought out anomalies previously obscured by regional Bouguer gravity anomalies, for example, the Rio Grande rift. This approach is most useful in areas where there are large lateral variations in the regional elevation of topography, for example between Texas and the high Central Mexican plateau. The method is also applicable to lateral variations in regional topography such as from the Llano Estacado to the Trans-Pecos.
The application of the regional elevation datum method is equivalent to the application of an isostatic correction to the Bouguer gravity anomaly values, but is far less complicated to apply than classic isostatic corrections.
Analysis of regional patterns trending between major tectonic and physiographic provinces has been facilitated greatly by generation of this type of residual anomaly map. Local anomalies such as basins also are defined better because of lack of distortion by large regional anomalies. A continuity also can be seen between the residual gravity anomaly trends in Arizona, New Mexico, and the area of this study.
AAPG Search and Discovery Article #90970©1977 AAPG Southwest Section Meeting, Abilene, Texas